Nanostructure materials, such as carbon nanotubes (CNT), possess promising properties, such as electron field emission characteristics which appear to be far superior to that of conventional field emitting materials. In particular, CNT materials exhibit low emission threshold fields as well as large emission current densities. Such properties make them attractive for a variety of microelectronic applications, such as lighting elements, field emission flat panel displays, gas discharge tubes for over voltage protection and x-ray generating devices. However, the effective incorporation of such materials into these devices has been hindered by difficulties encountered in the processing of such materials.
Electrophoretic deposition (EPD) is known to be a highly efficient and versatile technique for the deposition of nanostructure materials, including CNT, on a variety of substrates to produce novel coatings and films. An increasing interest in EPD techniques is driven by the availability of a variety of suitable materials, the technique's simplicity and low cost setup, the ability to control deposition, and the potential to scale-up to large dimensions.
The method of EPD can comprise the use of nanostructure materials, matrix materials and a substrate upon which the nanostructure materials are deposited. The matrix material is generally used to enhance the bonding of the nanostructure material with the substrate. For example, nanostructure materials and matrix materials can be co-deposited onto the substrate using EPD to form a composite film. However, composite films produced using this method can have less than desirable characteristics, particularly regarding uniformity of deposition, surface topography and adhesion strength. Thus, there is a need for a method of deposing nanostructure materials and matrix materials to form a composite film with improved surface uniformity, nanostructure material dispersion and adhesion between nanostructure materials and matrix materials.